Photomania- Stanford Paul Hegarty's class - iphone

Question

is there something wrong with core data for xcode 4.3.2
I'm following the Stanford Paul Hegarty class for ios 5.0
doing the core data walkthrough (Video 14 Core data demo)
I downloaded the file here
I ran it in xcode 4.3.2 but the core data doesn't seem to work because the entries in the tableview do not appear.
I tried to run it in another computer with xcode 4.2 and ios 5.0
it's working perfectly
anybody who encountered the same problem? I'm pretty sure that xcode is at fault.

Answer 1

Interesting. I am having the same problems and I am also using XCode 4.3, but just thought it was because of the Flickr license that you need and which I don't have. (In FlickAPIKey.h, there is a #define FlickrAPIKey #"" and you won't download anything if you don't have that key.)
Update: I got myself a Flickr API key (you can just get one from their website) and tried the Photomania App on XCode 4.3: it works like a charm, so it looks like XCode is not your problem here. (Although on occasion I found that I had to stop and restart XCode to get rid of a strange bug or compiler error.) Anyway, maybe it is an idea to delete the data first before you try again: Just delete the App before you run it and the database file will get deleted as well.

Answer 2

Paul Hegarty after his class, has published an update version of his code which have a call to SAVE the CoreData database! This may be the reason why your CoreData informations doesn't persist.
His update note was:
// should probably saveToURL:forSaveOperation:(UIDocumentSaveForOverwriting)completionHandler: here!
// we could decide to rely on UIManagedDocument's autosaving, but explicit saving would be better
// because if we quit the app before autosave happens, then it'll come up blank next time we run
// this is what it would look like (ADDED AFTER LECTURE) ...
[document saveToURL:document.fileURL forSaveOperation:UIDocumentSaveForOverwriting completionHandler:NULL];
So, you have to Add the 'document saveToURL' line in the 'fetchFlickrDataInDocument' function like this:
- (void)fetchFlickrDataIntoDocument:(UIManagedDocument *)document
{
dispatch_queue_t fetchQ = dispatch_queue_create("Flickr fetcher", NULL);
dispatch_async(fetchQ, ^{
NSArray *photos = [FlickrFetcher recentGeoreferencedPhotos];
[document.managedObjectContext performBlock:^{
// perform in the NSMOC's safe thread (main thread)
for (NSDictionary *flickrInfo in photos) {
[Photo photoWithFlickrInfo:flickrInfo inManagedObjectContext:document.managedObjectContext];
// table will automatically update due to NSFetchedResultsController's observing of the NSMOC
}
// should probably saveToURL:forSaveOperation:(UIDocumentSaveForOverwriting)completionHandler: here!
// we could decide to rely on UIManagedDocument's autosaving, but explicit saving would be better
// because if we quit the app before autosave happens, then it'll come up blank next time we run
// this is what it would look like (ADDED AFTER LECTURE) ...
[document saveToURL:document.fileURL forSaveOperation:UIDocumentSaveForOverwriting completionHandler:NULL];
// note that we don't do anything in the completion handler this time
}];
});
}

Answer 3

If someone is still facing the same issue using Objective-C, there is one more thing you need to do after getting API key: change all http:// to https:// within files in FlickrFetcher folder. This worked for me.